Joystick input devices have been employed in a wide range of applications, from aircraft control to video game inputs. Joysticks may be provided to supply directional input information related to a single rotational axis, or to multiple axes. More sophisticated joystick instruments may provide magnitude data as well.
In operation, an operator will manually displace the joystick relative to one or more of its rotational axes in order to issue directional commands to other equipment. Sensors within the joystick will sense the angular displacement of the joystick and develop input signals accordingly, which may be transmitted to the equipment to be controlled. The sensors and the signals they produce may operate electronically, hydraulically, or otherwise.
In many applications it is desirable that the joystick return to a center or neutral position after it has been released by the operator. Many joysticks are designed to be displaced about two perpendicular axes, so that directional information may be detected through 360 degrees. Thus, in order to return the joystick to a center position on one or both axes, certain designs have included springs to provide a centering force relative to each axis. While these mechanisms can provide the desired centering functions, these return mechanisms also tend to add weight, complexity, and cost to the design of the joystick, and cause the joystick to be mass unbalanced and therefore more susceptible to the effects of acceleration, e.g., to resist movement of the stick by gravity, g-forces.